中文摘要：

大气温室效应气体N2O、CO2增多与全球气温变暧有着密切的关系，由于农业活动导致的碳排放量占碳总排放量的25％，因此研究农田土壤有机碳的影响因素，对增加农田碳素固定和保持，减少由于不合理的土地使用而导致大量CO2的排放，维持农业和生物圈生态系统的可持续发展有着重要意义。本文分析了温度、永分、土地开垦、休闲和撩荒、耕鬣、轮作、秸秆还田、肥料管理等对土壤有机碳的影响。减少翻耕次数，增加秸秆还田，优化氮、磷、钾等养分用量及配比，是提高农田，尤其是旱地农田土壤有机碳含量，培肥、改良土壤的重要途径。

英文摘要：

The increase of greenhouse gas, such as N2O and CO2 has been proved to be the main factors leading global warming effects. Emission of CO2 caused by agricultural production is found to account for 25 % of the total carbon emission. Therefore, investigations of factors affecting soil organic C are of great importance for increasing C sequestration and retention in agricultural soil system, decreasing C emission caused unreasonable land utilization, and ensuring the sustainable development of agricultural and biospherical ecosystems. This pa- per discussed effects from factors, such as temperature, water, land reclamation, fallowing, tillage, rotation, straw retention, and fertilizer management, in order to rationalize land use and management. Reduce of tillage, increase of crop straw retention, and optimization of N, P and K fertilizer rate and ratio are proved to be an important ways to increase soil organic C content and its fertility and quality.